Rhizosphere competent Mesorhizobiumloti MP6 induces root hair curling, inhibits Sclerotinia sclerotiorum and enhances growth of Indian mustard (Brassica campestris)

Abstract

The bacterial strain Mesorhizobium loti MP6, isolated from root nodules of Mimosa pudica induced growth and yield of Brassica campestris. The isolate MP6 secreted hydroxamate type siderophore in Chrom-Azurol Siderophore (CAS) agar medium. Production of hydrocyanic acid (HCN), indole acetic acid (IAA) and phosphate solubilizing ability was also recorded under normal growth conditions. Root hair curling was observed through simple glass-slide technique. In vitro study showed a significant increase in population of M. loti MP6 in rhizosphere due to root exudates of B. campestris. In dual culture technique the strain showed a strong antagonistic effect against Sclerotinia sclerotiorum, a white rot pathogen of Brassica campestris. The growth of S. sclerotiorum was inhibited by 75% after prolonged incubation. Efficient root colonization of mustard seedlings was confirmed by using a streptomycin-resistant marker M. loti MP6 strep+ . The M. loti MP6 coated seeds proved enhanced seed germination, early vegetative growth and grain yield as compared to control. Also, a drastic decline (99%) in the incidence of white rot was observed due to application of M. loti MP6.

Exogenous glucosinolate produced by Arabidopsis thaliana has an impact on microbes in the rhizosphere and plant roots

“…Some other active Rhizobium populations are present in rhizospheric soil for both plant types, clearly implicated in the assimilation of root exudates but independently of glucosinolate profiles (Table 3). Mesorhizobium, frequently isolated from plant nodules Weir et al, 2004), had a plant growth promoting effect on Indian mustard Brassica campestris (Chandra et al, 2007) when Rhizobium species known for their symbiotic association with members of the Fabaceae (Leguminosae) or their ability to form tumours with many plants (Hirsch, 2004) were already isolated from rhizosphere in non-symbiotic context (Yanni et al, 1997;Berge et al, 2009). Bosea populations seemed to have active roles in the plant rhizosphere (Martin-Laurent et al, 2006;Dandie et al, 2007) and could grow on specific compounds produced by the root of transgenic Lotus Oger et al (2004).…”

Development of Mesorhizobium ciceri-Based Biofilms and Analyses of Their Antifungal and Plant Growth Promoting Activity in Chickpea Challenged by Fusarium Wilt

“…Pathogenic control by rhizobia is attributed to mycoparasitism, production of antifungal metabolites like hydrogen cyanide (HCN), antibiotics, siderophores, competition for nutrients and induction of plant defense mechanisms [20,44,45]. In our study, both the rhizobial isolates and T. viride alone exhibited good antifungal property in terms of growth inhibition of fungal mycelium (32.5, 30.14 and 26.57 % respectively).…”

“…Arfaoui et al [17] has reported suppression of Fusarium wilt of chickpea under in vitro and in vivo conditions by six rhizobial strains positive for HCN production. Chandra et al [45] also observed growth inhibition of Sclerotinia sclerotiorum causing white rot in Brassica campestris by HCN producing Rhizobium loti MP6. Biofilm formation is quite common in natural environments which provide its component microbial cells a certain degrees of protection and helps in their growth, survival and successful colonization [46].…”

La solubilización de fosfatos como estrategia microbiana para promover el crecimiento vegetal

“…Según Banerjee et al (2010), los microorganismos solubilizadores de fosfato han sido aislados de suelos rizosféricos de varias plantas de interés agrícola como arroz (Chaiharn y Lumyong, 2009), trigo (Ahmad et al, 2008), soya (Son et al, 2006) mostaza (Chandra et al, 2007), berenjena y chili (Ponmurugan y Gopi, 2006). Scervino et al (2010) evaluaron la capacidad de solubilización de varias fuentes de P por parte de aislamientos fúngicos aislados de la rizósfera de varios cultivos, que tienen la capacidad de ser agentes biocontroladores contra hongos patógenos como Sclerotinia sclerotiorum, y encontraron que cada aislado muestra diferentes patrones de producción de ácidos orgánicos, involucrados en la solubilización de sales de fosfato.…”